Concrete double-case subsection beam construction method

Abstract

The invention discloses a construction method of a concrete double-box segment girder, more particularly relates to the construction of the bridge segment girder, comprising the following steps: 1) the segment girder is hoisted to position and an oil-jacked support is installed; 2) a wet seam bracket and an internal template as well as an external template are installed, and wet seam concrete is cast; 3) after the wet seam concrete reaches the requirement of design strength, the internal template and the external template are removed and F6 and F5 are stretched; 4) the thickness of the mat ofthe oil-jacked support of the midspan segment girder is reduced by 30mm, and other oil-jacked supports are unloaded according to the parabola of degree 4; 5) after F4 to F1 are stretched, the limitation of a bridge fabrication machine to the girder body is released; 6) steel strands B5 to B1 are stretched; 7) a diaphragm plate is cast and a transversal prestress bundle is stretched; and 8) the bridge fabrication machine is hauled through a hole to carry out the construction of a lower hole girder. The method adopts stepped stretching and sorted unloading to reduce the action of the restoring force of the bridge fabrication machine on the girder body, thus avoiding the occurrence of larger pulling stress of the upper limb stress of the girder body, having simple method and strong operability, and not only being suitable for the prestress stretching of a double-wire simple supporting box girder, but also effectively guaranteeing the safety of the box girder structure.

Description

A construction method of concrete double-box segmental beam technical field The invention relates to the construction of bridge segmental beams, in particular to a construction method for concrete double-box segmental beams. Background technique The 64m Baima River Bridge on the Wenzhou-Fuzhou Railway Passenger Dedicated Line is a typical double-line simply supported box girder bridge. It is designed as a double-width single-box single-chamber section with a beam height of 5m. It is connected by 60cm wide cast-in-place wet joints. There are 12 wet joints in the whole beam, and the weight of the double-width concrete beam is 3200t; After being reviewed by experts, it was changed to a double-line erection scheme, and the construction method of "prefabricated segmental hoisting + in-situ cast-in-place wet joints + prestressed tensioned beams" was adopted. MZ3200t bridge-building machine was used for construction of this beam. Since segmental girder installation, wet joint po...

AI Technical Summary

Problems solved by technology

The restoring force during the unloading process of the bridge building machine may cause a large tensile stress on the upper edge of the beam body, thus affecting the safety of the beam body

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